Confocal laser endomicroscopy for the assessment of the mucosal healing process in Crohn's colitis and ulcerative colitis
Introduction: Mucosal healing (MH) is the main goal in the treatment of IBD. Monitoring of MH is important in evaluating the therapy response and the course of disease. By contrast to the macroscopic scores provided by conventional endoscopy in MH assessment, the analysis of the mucosal microstructure using confocal laser endomicroscopy (CLE) might give new insights into MH during therapy and define more precisely MH in Crohn's colitis (CC) and ulcerative colitis (UC).
Aims & methods: The aim was to investigate the utility of CLE for assessing microscopic mucosal changes before and after the start of anti-TNF alpha therapy in CC and UC. The morphological criteria of crypt number and architectural changes (distortion, crypt erosions/ulcerations) were evaluated for a MH score for IBD (IBD-MH score). Consecutive active UC patients (17; Mayo> 6) and CC patients (14; CDAI > 220) were prospectively included and underwent colonoscopy with CLE before and after 3 infliximab (IFX) infusions. Based on the Mayo-score and CDAI score, 2 groups i.e. therapy responders (Mayo< 3; CDAI< 150) and nonresponders (Mayo> 3; CDAI> 150) were defined (10 drop-outs). A total of 2.100 random endomicrographs from 21 patients (13 UC and 8 CC) were analyzed in a blinded fashion by 2 endoscopists (50 random micrographs/patient taken before and 50 after IFX therapy)- based on the IBD-MH score ranging from 0 to 9.
Results: Post-IFX, responder group IBD patients showed an increase in crypt number and a decrease of IBD-MH score. The differences between these two parameters were statistically significant in the responder group (p < 0,05). In the non-responder group, the differences between the pre- and post-treatment scores were not statistical significant (P > 0,05). MH was defined as IBD-MH score = 0.
Conclusion: Our new IBD-MH-score showed excellent accuracy with the therapy response assessed by clinical scores. Furthermore, microscopic aspects allow a more precise assessment of MH. CLE can accurately assess MH in vivo based on the newly developed and statistically validated IBD-MH-score for UC and CC.